Hand held photochromic marking implement

ABSTRACT

Disclosed is a hand-held photochromic marking implement including a photochromic colorant and solid phase colorant carrier which can be used in direct-to-media marking and a method of forming same.

BACKGROUND

Disclosed herein are hand held photochromic marking implements andmethods for making the same. More specifically, disclosed herein arehand-held marking implements that include a handle portion for grippingthe marking implement, and a marking portion comprising a solid carriermaterial and a photochromic colorant. In one embodiment the photochromiccolorant is substantially colorless when inactivated and a predeterminedcolor when activated. In another embodiment a method is provided forminga hand-held marking implement. This method can comprise forming flowablesolid carrier material including a photochromic colorant cooling andshaping the flowable carrier material. In this way a solid hand-heldmarking implement as described above can be formed.

In general, hand-held marking implements can have many structural formsand utilize many direct marking modes. The typical structure of amarking implement is a variation on an elongated, stick-like form, whichfacilitates controlled marking by the human hand. The common directmarking modes include deposition of either colored liquid substances,such as an ink, or colored solid phase substances, such as a graphite,chalk, or wax, onto a recording media. Marking implements comprising acolorant incorporated into a solid carrier of wax or chalk are commonlyreferred to as crayons. Crayons are in the solid phase at ambienttemperature, but are soft enough to deposit colored carrier materialdirectly onto a selected media.

Photochromism in general is a reversible change of a single chemicalspecies, a photochromogen, between two states having distinguishablydifferent absorption spectra, wherein the change is induced in at leastone state by the action of electromagnetic radiation. The inducingradiation, as well as the changes in the absorption spectra, are usuallyin the ultraviolet, visible, or infrared regions. In some instances, thechange in states is thermally induced. The photochromogen can be amolecule or an ion, and the reversible change in states may be aconversion between two molecules or ions, or the dissociation of asingle molecule or ion into two or more species, with the reverse changebeing a recombination of the two or more species thus formed into theoriginal molecule or ion. Photochromic phenomena are observed in bothorganic compounds, such as anils, disulfoxides, hydrazones, osazones,semicarbazones, stilbene derivatives, o-nitrobenzyl derivatives, spirocompounds, and the like, and in inorganic compounds, such as metaloxides, alkaline earth metal sulfides, titanates, mercury compounds,copper compounds, minerals, transition metal compounds such ascarbonyls, and the like. Photochromic materials are known inapplications such as eyeglasses, toys, clothing, and inks. Photochromicphase change ink compositions are described in U.S. Pat. Nos. 5,593,486and 5,759,729, which are incorporated herein in their entirety byreference.

A need remains for improved hand-held direct marking implements which,unlike conventional marking implements, have photochromiccharacteristics. These characteristics can provide, for example, theability to create marks that either become visible or change color stateupon activation. A need further remains for marking implements havingcompositions and structural shapes designed to be hand-held and capableof directly marking various recording media with a mark having amodifiable visual appearance. There is an artistic need for a hand-held,direct-to-media marking implement that can create a mark that can bereversibly modulated between a first color and a second color. There isalso a need for a simple, hand-held direct-to-media marking implementwhich enables the quick placement of a marking on a medium which is notreadily detectable until it is activated by a radiation source.

SUMMARY

Disclosed herein are hand held photochromic marking implements andmethods for making the same. As described above a hand-held markingimplement can be provided that includes a handle portion for grippingthe marking implement, and a marking portion comprising a solid carriermaterial and a photochromic colorant. In an embodiment described hereinthe photochromic colorant is substantially colorless when inactivatedand a predetermined color when activated. A further embodiment can beprovided comprising a method for forming a hand-held marking implement.This method can be as described above.

DETAILED DESCRIPTION

The marking implement as disclosed herein has a handle portion and atleast one marking portion. The marking portion may be a point, an edge,or a surface that can be used to write or mark on a recording medium. Inone embodiment, the marking implement has a generally elongated,stick-like handle portion that can be comfortably grasped by the hand ofa user and the marking portion has a tapered shape adapted for marking.At least the marking portion of this embodiment comprises a solid phasecarrier material and a photochromic colorant. Depending on the specificembodiment, the handle portion may also comprise the solid carriermaterial and photochromic colorant. In a particular embodiment, thehandle portion of the marking implement is comprised primarily of thecarrier material and thus the physical properties of the both the handleportion and the marking portion depend directly on the physicalproperties of the carrier material. In another embodiment, the handleportion of the marking implement comprises the carrier material embeddedwithin an outer cladding, wherein the physical properties of the markingimplement handle portion depends only indirectly on the physicalproperties of the carrier material. In still other embodiments, thehandle portion of the marking implement does not comprise any of thecarrier material and only the marking portion contains the carriermaterial and photochromic colorant.

In the exemplary compositions described below, the solid phase carriercomprises a low polarity wax to control the melting point, softness, andbasic physical properties of the carrier material. These mechanicalfactors influence the durability and marking or writing performance ofthe solid phase carrier, such as resistance to breakage and bending ofthe marking portion of the implement, pressure needed to mark arecording medium, smoothness of marking, adhesion of marking, andminimization of crumbling and other undesired phenomena when marking. Itis commonly known in the art that as the melting point of the lowpolarity wax is reduced, the wax becomes mechanically softer. Thus, thehardness of the carrier material can be tailored by first choosing a waxof a particular melting or softening point and then choosing the percentcomposition of the particular wax in the carrier material. Inembodiments of the present invention, the low polarity wax can beparaffins, microcrystalline waxes, polyethylene waxes, ester waxes,amide waxes, such as a tetra-amide wax, fatty acids, fatty alcohols,such as the UNILIN® products available from Baker Petrolite, fattyamides and other waxy materials, sulfonamide materials, resinousmaterials made from different natural sources (such as, for example,tall oil rosins and rosin esters), and many synthetic resins, oligomers,polymers and copolymers, such as ethylene/vinyl acetate copolymers,ethylene/acrylic acid copolymers, ethylene/vinyl acetate/acrylic acidcopolymers, copolymers of acrylic acid with polyamides, and the like,ionomers, and the like, as well as mixtures thereof. In particularembodiments of the present invention, the low polarity wax can bePolyethylene Wax 5300 or Polyethylene Wax 8400, both made by MitsuiChemical. In still other particular embodiments of the presentinvention, a polyalkylene wax, such as a polyethylene wax, apolypropylene wax, or mixtures thereof. Examples of suitablepolyalkylene waxes include POLYWAX® 400 and POLYWAX® 500 (commerciallyavailable from Baker Petrolite), Vybar 103 and 253, commerciallyavailable from Baker Petrolite, POLYWAX® 655 and higher molecular weightpolywax materials are also suitable. In other particular embodiments ofthe present invention, the low polarity wax is a fatty amide-containingmaterial such as a tetra-amide wax compound. The preferred tetra-amidewax compounds for producing the phase change ink carrier composition areDimer acid-based tetra-amides which preferably include the reactionproduct of a fatty acid, a diamine (ethylene diamine) and a Dimer acid.Fatty acids having from 10 to 22 carbon atoms can be employed in theformation of the Dimer acid-based tetra-amide. Dimer acid-basedtetra-amides can be those produced by Union Camp and comprise thereaction product of ethylene diamine, Dimer acid, and the followingfatty acids: decanoic acid (Union Camp X3202-23), myristic acid (UnionCamp X3202-56), stearic acid (Union Camp X3138-43, X3164-23, X3202-44,X3202-46, X3222-65, X3261-37, X3261-53, and X3290-72), docasanic acid(Union Camp X3202-36). For purposes of this invention, the mostpreferred Dimer acid-based tetraamide is the reaction product of Dimeracid, ethylene diamine and stearic acid in a stoichiometric ratio of1:2:2. Stearic acid is the preferred fatty acid reactant because itsadduct with Dimer acid and ethylene diamine has the lowest viscosity ofthe Dimer acid-based tetra-amides. Its ingredients also are the mostreadily available and therefore lowest in cost. In one such embodiment,the Dimer acid-based tetra-amide material is Unirez resin, made by UnionCamp Corporation. Dimer acid-bawed tetra-amides can be prepared asdisclosed in, for example, U.S. Pat. No. 6,174,937, the disclosure ofwhich is totally incorporated herein by reference.

Depending on the desired mechanical properties and the low polarity waxchosen for a particular embodiment. The low polarity wax(es) can bepresent in the carrier material in one embodiment of at least about 20percent by weight, in another embodiment of at least about 25 percent byweight, and in yet another embodiment of at least about 30 percent byweight, and in one embodiment equal to or less than about 50 percent byweight, in another embodiment equal to or less than about 55 percent byweight of the ink carrier, and in yet another embodiment equal to orless than about 60 percent by weight of the ink carrier, although theamount can be outside of these ranges.

In certain embodiments, the solid phase carrier material includes amechanical strengthening agent, thereby lowering the percent compositionof low polarity wax in the carrier material. In particular embodiments,a tackifier resin is the mechanical strengthening. In certainembodiments, tackifiers, such as FORAL® 85, a glycerol ester ofhydrogenated abietic (rosin) acid (commercially available fromHercules), FORAL® 105, a pentaerythritol ester of hydroabietic (rosin)acid (commercially available from Hercules), CELLOLYN® 21, ahydroabietic (rosin) alcohol ester of phthalic acid (commerciallyavailable from Hercules), ARAKAWA KE-311 and KE-100 Resins,triglycerides of hydrogenated abietic (rosin) acid (commerciallyavailable from Arakawa Chemical Industries, Ltd.), synthetic polyterpeneresins such as NEVTAC® 2300, NEVTAC® 100, and NEVTAC® 80 (commerciallyavailable from Neville Chemical Company), WINGTACK® 86, a modifiedsynthetic polyterpene resin (commercially available from Goodyear), andthe like, can be utilized.

In certain embodiments, the mechanical strengthening agent is apolyurethane resin. Suitable materials also can includeisocyanate-derived resins and waxes, such as urethane isocyanate-derivedmaterials, urea isocyanate-derived materials, urethane/ureaisocyanate-derived materials, mixtures thereof, and the like. Furtherinformation on isocyanate-derived carrier materials is disclosed in, forexample, U.S. Pat. No. 5,750,604, U.S. Pat. No. 5,780,528, U.S. Pat. No.5,782,966, U.S. Pat. No. 5,783,658, U.S. Pat. No. 5,827,918, U.S. Pat.No. 5,830,942, U.S. Pat. No. 5,919,839, U.S. Pat. No. 6,255,432, U.S.Pat. No. 6,309,453, British Patent GB 2 294 939, British Patent GB 2 305928, British Patent GB 2 305 670, British Patent GB 2 290 793, PCTPublication WO 94/14902, PCT Publication WO 97/12003, PCT Publication WO97/13816, PCT Publication WO 96/14364, PCT Publication WO 97/33943, andPCT Publication WO 95/04760, the disclosures of each of which areincorporated herein in their entirety by reference.

In one embodiment, the tackifier can be present in the carrier materialin one embodiment of at least about 10 percent by weight, in anotherembodiment of at least about 15 percent by weight, and in yet anotherembodiment of at least about 20 percent by weight, and in one embodimentequal to or less than about 40 percent by weight, in another embodimentequal to or less than about 45 percent by weight of the ink carrier, andin yet another embodiment equal to or less than about 50 percent byweight of the ink carrier, although the amount can be outside of theseranges.

In certain embodiments of the present invention, the carrier materialincludes a dye solubility agent to enhance the solubility of thecolorants in the carrier material. In further embodiments suitable dyesolubility agents can comprise fatty acids include fatty amides, such asmono-amides, tetra-amides, mixtures thereof, and the like. Specificexamples of suitable fatty amide ink carrier materials include stearylstearamide, a dimer acid based tetra-amide that is the reaction productof dimer acid, ethylene diamine, and stearic acid, a dimer acid basedtetra-amide that is the reaction product of dimer acid, ethylenediamine, and a carboxylic acid having at least about 36 carbon atoms,and the like, as well as mixtures thereof. When the fatty amide inkcarrier is a dimer acid based tetra-amide that is the reaction productof dimer acid, ethylene diamine, and a carboxylic acid having at leastabout 36 carbon atoms, the carboxylic acid is of the general formula

wherein R is an alkyl group, including linear, branched, saturated,unsaturated, and cyclic alkyl groups, said alkyl group in one embodimenthaving at least about 36 carbon atoms, in another embodiment having atleast about 40 carbon atoms, said alkyl group in one embodiment havingno more than about 200 carbon atoms, in another embodiment having nomore than about 150 carbon atoms, and in yet another embodiment havingno more than about 100 carbon atoms, although the number of carbon atomscan be outside of these ranges. Carboxylic acids of this formula arecommercially available from, for example, Baker Petrolite, Tulsa, Okla.,and can also be prepared as described in Example 1 of U.S. Pat. No.6,174,937, the disclosure of which is totally incorporated herein byreference. Further information on fatty amide carrier materials isdisclosed in, for example, U.S. Pat. No. 4,889,560, U.S. Pat. No.4,889,761, U.S. Pat. No. 5,194,638, U.S. Pat. No. 4,830,671, U.S. Pat.No. 6,174,937, U.S. Pat. No. 5,372,852, U.S. Pat. No. 5,597,856, U.S.Pat. No. 6,174,937, and British Patent GB 2 238 792, the disclosures ofeach of which are totally incorporated herein by reference.

In one embodiment, the fatty acid solubility agent can be present in thecarrier material in one embodiment of at least about 30 percent byweight, in another embodiment of at least about 40 percent by weight,and in yet another embodiment of at least about 50 percent by weight,and in one embodiment equal to or less than about 70 percent by weight,in another embodiment equal to or less than about 80 percent by weightof the ink carrier, and in yet another embodiment equal to or less thanabout 90 percent by weight of the ink carrier, although the amount canbe outside of these ranges.

In some embodiments of the present invention, the carrier materialincludes a visible, non-photochromic colorant. Inclusion of a visiblecolorant in the carrier material composition permits the markings to beviewed as they are made. The non-photochromic colorant can be anycommonly known dye or pigment that has an appropriate solubility in thecarrier material and the desired color. Selection of the color can bemade to achieve a desired color combination with a photochromic colorantupon activation of the photochromogen. For example, if a yellow dye isused, markings will have a visible yellow color changing into a blackishcolor by additive coloration upon activation of the photochromiccolorant. Any desired or effective non-photochromic colorant can beemployed, including dyes, pigments, mixtures thereof, and the like,provided that the non-photochromic colorant can be dissolved ordispersed in the solid phase carrier material. The solid carriercompositions can be used in combination with conventional colorantmaterials, such as Color Index (C.I.) Solvent Dyes, Disperse Dyes,modified Acid and Direct Dyes, Basic Dyes, Sulphur Dyes, Vat Dyes, andthe like. Examples of suitable dyes include Neozapon Red 492 (BASF);Orasol Red G (Ciba-Geigy); Direct Brilliant Pink B (Crompton & Knowles);Aizen Spilon Red C-BH (Hodogaya Chemical); Kayanol Red 3BL (NipponKayaku); Levanol Brilliant Red 3BW (Mobay Chemical); Levaderm LemonYellow (Mobay Chemical); Spirit Fast Yellow 3G; Aizen Spilon YellowC-GNH (Hodogaya Chemical); Sirius Supra Yellow GD 167; CartasolBrilliant Yellow 4GF (Sandoz); Pergasol Yellow CGP (Ciba-Geigy); OrasolBlack RLP (Ciba-Geigy); Savinyl Black RLS (Sandoz); Dermacarbon 2GT(Sandoz); Pyrazol Black BG (ICI); Morfast Black Conc. A(Morton-Thiokol); Diaazol Black RN Quad (ICI); Orasol Blue GN(Ciba-Geigy); Savinyl Blue GLS (Sandoz); Luxol Blue MBSN(Morton-Thiokol); Sevron Blue 5GMF (ICI); Basacid Blue 750 (BASF),Neozapon Black X51 [C.I. Solvent Black, C.I. 12195] (BASF), Sudan Blue670 [C.I. 61554] (BASF), Sudan Yellow 146 [C.I. 12700] (BASF), Sudan Red462 [C.I. 26050] (BASF), Intratherm Yellow 346 from Crompton andKnowles, C.I. Disperse Yellow 238, Neptune Red Base NB543 (BASF, C.I.Solvent Red 49), Neopen Blue FF-4012 from BASF, Lampronol Black BR fromICI (C.I. Solvent Black 35), Morton Morplas Magenta 36 (C.I. Solvent Red172), metal phthalocyanine colorants such as those disclosed in U.S.Pat. No. 6,221,137, the disclosure of which is totally incorporatedherein by reference, and the like. Polymeric dyes can also be used, suchas those disclosed in, for example, U.S. Pat. No. 5,621,022 and U.S.Pat. No. 5,231,135, the disclosures of each of which are totallyincorporated herein by reference, and commercially available from, forexample, Milliken & Company as Milliken Ink Yellow 12, Milliken Ink Blue92, Milliken Ink Red 357, Milliken Ink Yellow 1800, Milliken Ink Black8915-67, uncut Reactant Orange X-38, uncut Reactant Blue X-17, SolventYellow 162, Acid Red 52, Solvent Blue 44, and uncut Reactant VioletX-80.

Use of a non-photochromic dye is a particularly elegant embodiment ofthe present invention because pigments give color through lightscattering and light refraction, which risks interfering with activationof the photochromic colorant (which develops through light absorbance).However, the use of a non-photochromic pigment is also within the scopeof the present invention. Examples of suitable non-photochromic pigmentsinclude Violet Toner VT-8015 (Paul Uhlich); Paliogen Violet 5100 (BASF);Paliogen Violet 5890 (BASF); Permanent Violet VT 2645 (Paul Uhlich);Heliogen Green L8730 (BASF); Argyle Green XP-111-S (Paul Uhlich);Brilliant Green Toner GR 0991 (Paul Uhlich); Lithol Scarlet D3700(BASF); Toluidine Red (Aldrich); Scarlet for Thermoplast NSD PS PA(Ugine Kuhlmann of Canada); E.D. Toluidine Red (Aldrich); Lithol RubineToner (Paul Uhlich); Lithol Scarlet 4440 (BASF); Bon Red C (DominionColor Company); Royal Brilliant Red RD-8192 (Paul Uhlich); Oracet PinkRF (Ciba-Geigy); Paliogen Red 3871K (BASF); Paliogen Red 3340 (BASF);Lithol Fast Scarlet L4300 (BASF); Heliogen Blue L6900, L7020 (BASF);Heliogen Blue K6902, K6910 (BASF); Heliogen Blue D6840, D7080 (BASF);Sudan Blue OS (BASF); Neopen Blue FF4012 (BASF); PV Fast Blue B2GO1(American Hoechst); Irgalite Blue BCA (Ciba-Geigy); Paliogen Blue 6470(BASF); Sudan III (Red Orange) (Matheson, Colemen Bell); Sudan II(Orange) (Matheson, Colemen Bell); Sudan Orange G (Aldrich), SudanOrange 220 (BASF); Paliogen Orange 3040 (BASF); Ortho Orange OR 2673(Paul Uhlich); Paliogen Yellow 152, 1560 (BASF); Lithol Fast Yellow0991K (BASF); Paliotol Yellow 1840 (BASF); Novoperm Yellow FGL(Hoechst); Permanent Yellow YE 0305 (Paul Uhlich); Lumogen Yellow D0790(BASF); Suco-Yellow L1250 (BASF); Suco-Yellow D1355 (BASF); Suco FastYellow D1355, D1351 (BASF); Hostaperm Pink E (American Hoechst); FanalPink D4830 (BASF); Cinquasia Magenta (Du Pont); Paliogen Black L0084(BASF); Pigment Black K801 (BASF); and carbon blacks such as Regal 3300(Cabot), Carbon Black 5250, Carbon Black 5750 (Columbia Chemical), andthe like.

Also suitable, are the non-photochromic colorants disclosed in U.S. Pat.No. 6,472,523, U.S. Pat. No. 6,726,755, U.S. Pat. No. 6,476,219, U.S.Pat. No. 6,576,747, U.S. Pat. No. 6,713,614, U.S. Pat. No. 6,663,703,U.S. Pat. No. 6,755,902, U.S. Pat. No. 6,590,082, U.S. Pat. No.6,696,552, U.S. Pat. No. 6,576,748, U.S. Pat. No. 6,646,111, U.S. Pat.No. 6,673,139, Copending Application U.S. Ser. No. 10/260,146, filedSep. 27, 2002, entitled “Colorant Compounds,” and Copending ApplicationU.S. Ser. No. 10/260,379, filed Sep. 27, 2002, entitled “Methods forMaking Colorant Compounds,” the disclosures of each of which are totallyincorporated herein by reference.

In a specific embodiment, the non-photochromic colorant is anisocyanate-derived colored resin as disclosed in, for example, U.S. Pat.No. 5,780,528 and U.S. Pat. No. 5,919,839, the disclosures of each ofwhich are totally incorporated herein by reference. In such anembodiment, the mechanical strengthening and visible colorant featuresare combined. In this embodiment, the colorant is the reaction productof a hydroxyl-substituted or primary or secondary amino-substitutedchromophore with an isocyanate. Examples of suitable isocyanates includemonoisocyanates, diisocyanates, triisocyanates, copolymers of adiisocyanate, copolymers of a triisocyanate, polyisocyanates (havingmore than three isocyanate functional groups), and the like, as well asmixtures thereof. Specific examples of suitable isocyanates includethose listed hereinabove as being suitable for reaction with thehydroxyl-substituted or amino-substituted antioxidant. Examples ofsuitable hydroxyl-substituted and primary or secondary amino-substitutedchromophores include those disclosed in, for example, U.S. Pat. No.3,157,633, U.S. Pat. No. 3,927,044, U.S. Pat. No. 3,994,835, U.S. Pat.No. 4,102,644, U.S. Pat. No. 4,113,721, U.S. Pat. No. 4,132,840, U.S.Pat. No. 4,137,243, U.S. Pat. No. 4,170,564, U.S. Pat. No. 4,284,729,U.S. Pat. No. 4,507,407, U.S. Pat. No. 4,640,690, U.S. Pat. No.4,732,570, U.S. Pat. No. 4,751,254, U.S. Pat. No. 4,751,254, U.S. Pat.No. 4,761,502, U.S. Pat. No. 4,775,748, U.S. Pat. No. 4,812,141, U.S.Pat. No. 4,846,846, U.S. Pat. No. 4,871,371, U.S. Pat. No. 4,912,203,U.S. Pat. No. 4,978,362, U.S. Pat. No. 5,043,013, U.S. Pat. No.5,059,244, U.S. Pat. No. 5,149,800, U.S. Pat. No. 5,177,200, U.S. Pat.No. 5,270,363, U.S. Pat. No. 5,290,921, and U.S. Pat. No. 5,731,398, thedisclosures of each of which are totally incorporated herein byreference.

The non-photochromic colorant is present in the solid phase carrier inany desired or effective amount to obtain the desired color or hue. Inone embodiment of the present invention, the quantity of colorant isabout 0.1 percent by weight of the carrier material. In a furtherembodiment, the colorant is about 0.5 percent by weight of the carriermaterial, and in another embodiment about 1 percent by weight of theink. In yet another embodiment, the amount colorant is no more thanabout 5 percent by weight of the carrier material, and in still anotherembodiment the colorant forms no more than about 10 percent by weightthe of the carrier material.

Embodiments of the present invention incorporate a variety ofphotochromic colorants with a variety of carrier materials. As usedherein, “photochromic” is intended to describe changes in color orchanges from colorless to colorful upon activation. “Photochromic” isnot intended to include a colorant which has a first color when exposedto a first segment of the visible light spectrum and a second colorappearance upon exposure to a second segment of the visible lightspectrum. Activation is achieved in one embodiment by exposure toelectromagnetic radiation. In another embodiment photochromic colorantis activated by electromagnetic radiation having an ultravioletwavelength. The can be accomplished in the wavelength or energy rangecommonly consider within the ultraviolet spectrum. Examples of suchultraviolet absorbing dyes are disclosed in, for example, U.S. Pat. No.5,378,574, U.S. Pat. No. 5,146,087, U.S. Pat. No. 5,145,518, U.S. Pat.No. 5,543,177, U.S. Pat. No. 5,225,900, U.S. Pat. No. 5,301,044, U.S.Pat. No. 5,286,286, U.S. Pat. No. 5,275,647, U.S. Pat. No. 5,208,630,U.S. Pat. No. 5,202,265, U.S. Pat. No. 5,271,764, U.S. Pat. No.5,256,193, U.S. Pat. No. 5,385,803, and U.S. Pat. No. 5,554,480, thedisclosures of each of which are incorporated herein in their entiretyby reference.

Examples of suitable photochromic colorants include compounds thatundergo heterolytic cleavage, such as spiropyrans, benzospiropyrans,related compounds, and the like; compounds that undergo homolyticcleavage, such as bis-imidazole compounds, bis-tetraphenylpyrrole,hydrazine compounds, aryl disulfide compounds, and the like; compoundsthat undergo cis-trans isomerization, such as stilbene compounds,photoisomerizable azo compounds, and the like; compounds that undergophotochromic tautomerism, including those that undergo hydrogen transferphototautomerism, those that undergo photochromic valence tautomerism,and the like; including those disclosed in U.S. Pat. No. 5,759,729, thedisclosure of which is incorporated herein in its entirety by reference.As an illustrative example, a photochromic spirobenzopyran can be formedby combining an indoline derivative with 5-nitrosalicylaldehyde.

Various colors can be obtained through the use of different photochromiccolorants. For example,1′3′-Dihydro-1′,3′,3′-trimethyl-6-nitrospiro-[2H-1-benzopyran-2,2′-(2H)-indole],available from Aldrich Chemical Co., Milwaukie, Wis., having thestructure:

develops to a purple-black upon exposure to ultraviolet light. Anotherexemplary photochromic material is 1′-Dodecyl-6-nitro BIPS, where BIPSis Spiro (2H-1-benzopyran-2,2′-indoline, available from ChromaChemicals, Dayton, Ohio. Yet another exemplary photochromic material is1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphtha[2,1-b]-[1,4]oxazine,available from Aldrich Chemical Company, Milwaukee, Wis.

The photochromic colorant is present in the solid phase carrier in anydesired or effective amount to obtain the desired color or hue. In oneembodiment of the present invention, the quantity of colorant is about0.1 percent by weight of the carrier material. In a further embodiment,the colorant is about 0.5 percent by weight of the carrier material, andin another embodiment about 1 percent by weight of the ink. In yetanother embodiment, the amount colorant is no more than about 5 percentby weight of the carrier material, and in still another embodiment thecolorant forms no more than about 10 percent by weight the of thecarrier material.

Specific hand held marking implement embodiments will now be describedin detail. These examples are intended to be illustrative, and theclaims are not limited to the materials, conditions, or processparameters set forth in these particular embodiments.

EXAMPLE 1

A photochromic marking implement was prepared in a stainless steelbeaker by adding: (1) about 317 grams (52 wt %) of stearyl stearamide(KEMAMIDE S-180, obtained from Witco Corp.; (2) about 155.3 grams (26 wt%) of a glycerol ester of hydrogenated (rosin) acid tackifier resin(KE-100, obtained from Arakawa Chemical Industries, Ltd, Osaka, Japan);and (3) about 126.6 grams (21 wt %) of Unirez 2970 (a tetra-amide resinobtained from the reaction of one equivalent of dimer acid with twoequivalents of ethylene diamine and two equivalents of stearic acid).These materials were melted together in a heating mantle at atemperature of about 110° C. After stirring for about 30 minutes atabout 500 rpm, to this mixture was then added (4) 0.8 grams (1 wt %) ofphotochromic colorant (formed by the reaction of one mole of Fischer'sBase and one mole of 5-nitrosalicylaldehyde). The mixture was stirredfor about 10 additional minutes, poured into molds and then cooled toroom temperature to solidify. The solid was then removed from the moldsand labeled with paper sleeves indicating the color that appears afterexposure to electromagnetic radiation.

EXAMPLE 2

A photochromic marking implement was prepared in a four-ounce beaker byadding: (1) about 20 grams (25 wt %) of stearyl stearamide (KEMAMIDES-180, obtained from Witco Corp.; (2) about 20 grams (25 wt %) of aurethane resin having the composition of Example 1, U.S. Pat. No.6,620,228, the disclosure of which is totally incorporated herein byreference; and (3) 40 grams (50 wt %) of Polyethylene Wax 8400, obtainedfrom Mitsui Chemical. These materials were melted together in a 140° C.silicone oil bath under magnetic stirring conditions. After the mixturebecame molten, then was added (4) about 0.8 grams (1 wt %) of anultraviolet-responsive chromogenic colorant(1′3′-Dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole](Aldrich Chemical #27361-9)). This mixture was then stirred for about 30additional minutes, poured into molds and then cooled to roomtemperature to solidify. The solid was then removed from the molds andlabeled with paper sleeves indicating the color that appears afterexposure to electromagnetic radiation.

EXAMPLE 3

A marking implement was prepared as described in Example 2 except thatabout 40 grams of Polyethylene wax 5300 (Mitsui Chemical) was utilizedin place of the 40 grams of Polyethylene 8400.

EXAMPLE 4

A marking implement was prepared as described in Example 2 except thatabout 40 grams of POLYWAX® 655 (available from Baker Petrolite, Tulsa,Okla.) was utilized in place of the 40 grams of Polyethylene Wax 8400.

EXAMPLE 5

A marking implement was prepared as described in Example 2 except thatabout 40 grams of POLYWAX® 500 (available from Baker Petrolite, Tulsa,Okla.) was utilized in place of the 40 grams of Polyethylene Wax 8400.

The marking implements of the present invention were used to directlymark on paper recording media by hand. The marks made were not visibleto the human eye until placed in natural light, a portion of which iscomprised of ultraviolet electromagnetic radiation. The ultravioletlight activated the photochromic colorant in the marking and the markbecame visible. Upon subsequent removal of the sample from theultraviolet radiation source, the mark returned to the deactivatedstate, wherein the mark was again not visible to the human eye. Themarking can “disappear” and “reappear” a multitude of time upon additionor removal of radiation source.

While the embodiments disclosed herein are particularly graceful modesof the present invention, it should be appreciated that various of theabove-disclosed and other features and functions, or alternativesthereof, may be desirably combined into many other different systems orapplications. Also that various presently unforeseen or unanticipatedalternatives, modifications, variations or improvements therein may besubsequently made by those skilled in the art which are also intended tobe encompassed by the following claims.

1. A hand held marking implement comprising: a handle portion forgripping said marking implement; and at least one marking portioncomprising a solid phase carrier material and a photochromic colorant.2. The marking implement of claim 1, wherein the photochromic colorantis substantially colorless when inactivated and a predetermined colorwhen activated.
 3. The marking implement of claim 1, wherein saidphotochromic colorant is activated by electromagnetic radiation
 4. Themarking implement of claim 3, wherein said electromagnetic radiation hasan ultraviolet wavelength.
 5. The marking implement of claim 1, whereinthe photochromic colorant comprises at least one of1′3′-Dihydro-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole],1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]naphtha[2,1-b][1,4]oxazine, and mixtures thereof.
 6. The marking implement ofclaim 1, wherein the photochromic colorant comprises at least one ofbisimidazole compounds, bis-tetraphenylpyrrole compounds, hydrazinecompounds, aryl disulfide compounds, stilbene compounds, aromatic azocompounds, and mixtures thereof.
 7. The marking implement of claim 1,wherein the carrier material further comprises a non-photochromiccolorant.
 8. The marking implement of claim 1, wherein the carriermaterial includes a mechanical strengthening agent.
 9. The markingimplement of claim 8, wherein the mechanical strengthening agentcomprises a resin tackifier.
 10. The marking implement of claim 1,wherein the solid phase carrier material comprises at least one lowpolarity wax.
 11. The marking implement of claim 10, wherein the lowpolarity wax comprises a polyethylene wax.
 12. The marking implement ofclaim 10, wherein the low polarity wax comprises a tetra-amide wax. 13.The marking implement of claim 1, wherein the solid phase carriermaterial further includes a dye solubility agent.
 14. The markingimplement of claim 13, wherein the dye solubility agent is a fatty acid.15. The marking implement of claim 1, wherein said handle portion isembedded within an outer cladding.
 16. A method of forming a hand-heldmarking implement comprising: forming a flowable solid carrier materialincluding a photochromic colorant; cooling and shaping said flowablecarrier material; and forming a solid hand-held marking implementcomprising a handle portion for gripping said marking implement and amarking portion comprising said solid carrier material and saidphotochromic colorant.
 17. The method of claim 16, further comprisingshaping said solid hand-held marking implement by cooling said flowablecarrier material in a mold.
 18. The method of claim 16, furthercomprising wrapping said handle portion with an outer cladding.
 19. Themethod of claim 16, wherein the photochromic colorant is substantiallycolorless when inactivated and a predetermined color when activated. 20.The method of claim 16, wherein said photochromic colorant is activatedby electromagnetic radiation having an ultraviolet wavelength.
 21. Ahand held marking implement comprising: a handle portion for grippingsaid marking implement; and at least one marking portion comprising asolid phase carrier material and a photochromic colorant, wherein thephotochromic colorant is substantially colorless when inactivated and apredetermined color when activated by electromagnetic radiation.